The health status of the oral cavity is in large part influenced by constituents in saliva. The principal function of salivary glands, is the production of this complex fluid. To study the mechanisms controlling secretion of salivary components we have utilized both in vitro and in vivo animal preparations. As probes of secretory events we have focused our studies primarily on perturbations in neurotransmitter mediated control of gland secretory functions that occur with normal aging. Secondly, we have begun to examine the mechanism of radiation damage to salivary glands. In these studies we have examined (1) the mechanism of Ca++ mobilization, associated with secretory events, in vitro with rat parotid gland cells; (2) regulation of protein production in rat submandibular gland cells in vitro and its relationship to Ca++ mobilization; (3) protein synthesis and processing in different aged rat submandibular cells in vitro; (4) parasympathetic control of fluid, electrolyte, and protein release from parotid and submandibular glands of different aged rats, in vivo; (5) the in vitro responsiveness of rat parotid cells irradiated in vivo.